As described for example in U.S. Pat. No. 4,191,596, there has been a growing environmental concern over the chromate conversion coatings used to improve the corrosion resistance and paint adhesion properties of non-ferrous metal surfaces. This patent also describes some of the proposed alternative coating solutions based on the use of (a) polyacrylic acid or esters thereof and (b) fluoride compounds such as fluozirconic acid, though it teaches that AZF yields poor coatings (columns 5-6, Comparison D).
Applicants are not aware of any literature disclosing the use of coating solutions based on a combination of APPC and AZF.